Small tweak

inabox.wpf/DynamicGrid/DynamicGridColumns.cs

@@ -79,9 +79,10 @@ public class DynamicGridColumnGrouping
 {
     public List<DynamicGridColumnGroup> Groups = new();
 
-    public void AddGroup(string header, DynamicColumnBase start, DynamicColumnBase end)
+    public DynamicGridColumnGrouping AddGroup(string header, DynamicColumnBase start, DynamicColumnBase end)
     {
         Groups.Add(new(header, start, end));
+        return this;
     }
 }